Washington (CNN) -- The Obama administration has notified Congress of plans for a multiyear, multibillion-dollar weapons deal with Saudi Arabia, a State Department official said Wednesday.

The sale is meant to further align the Saudi military relationship with the United States and enhance the ability of the kingdom to defer and defend threats to it and its oil structure, which "is critical to our economic interests," said Andrew Shapiro, assistant secretary for political and military affairs, at a State Department news conference.

The deal, worth up to $60 billion over 20 years, will include the sale of 84 F-15 aircraft, the upgrade of 70 older-model F-15 aircraft and almost 200 helicopters.